What do women want? It’s the age-old question. But a recent study offers men a clue: women are most satisfied when their partner knows they’re upset.

Huh? According to the new study [PDF], published in the Journal of Family Psychology, relationship satisfaction has a lot to do with the way partners are able to read and empathize with each other’s emotions. For women, that applies more to their negative emotions than their positive ones: women are happy when their boyfriend or partner understands they’re upset.

For men, it’s somewhat simpler — they’re happy when their partner is happy. Men report more relationship satisfaction when they know their woman is happy, and not when they know she’s upset or angry.

For the study, researchers recruited 156 heterosexual dating or married couples and asked each person individually to describe a recent incident in which their partner did something that angered or disappointed them (like lying about his or her whereabouts). The couples were then brought together, presented with each partner’s grievance and asked to talk about the problem for 8 to 10 minutes and come to a better understanding of what happened. The researchers videotaped the interactions.

Afterward, the participants watched the videotape and continuously rated their emotional responses throughout, using an electronic rating device with a scale ranging from “very negative” to “neutral” to “very positive.” The researchers then selected six 30-second clips from the videotape that had the highest negative or positive emotional ratings from each partner. The participants watched the clips and rated their own and their partner’s feelings and their partner’s efforts to be empathetic.

Surprisingly, the researchers found, women were more likely to report higher relationship satisfaction when they could read their partners’ anger or frustration than when they could identify their happiness. No, it’s not that women revel in their significant others’ distress; rather, it’s that they prefer negative emotion to withdrawal or silence. “For women, seeing their husband or boyfriend upset is a reflection of their partner’s emotional engagement. When women see their male partners sharing their negative emotions, they see it as a sign of connection, openness and communication. Women don’t like it when men distance themselves during conflict,” says the study’s lead author, Dr. Shiri Cohen of Harvard Medical School.

Conversely, men don’t always like to share in their wife’s or girlfriend’s negativity. While women in the study were happier when their man knew they were upset, that knowledge made men unhappy. Men’s relationship satisfaction was tied to their ability to identify their partner’s happiness. The researchers suggest that’s because men — unlike women — may feel that the relationship is threatened by their partner’s negative emotions, especially when they arise in the middle of a relationship-related conflict.

Relationships are confusing, but based on the study, this is what it comes down to: the more communicative and empathetic men and women try to be in their relationships, the happier everyone is.

“When women emphasize what makes them happy in the relationship and express it in a way their male partners can easily read, this gives their partner a satisfaction boost,” says Dr. Cohen. “Men, women want to know when you’re upset. Even if it is uncomfortable, expressing these emotions will make women feel better in the relationship.”

For both parties, the researchers stress the importance of simply trying to understand each other. “Demonstrating in some way that you are trying, even if you are not getting it right, is what’s most important for relationship satisfaction,” says Cohen.